Fair Value of Financial Instruments (Tables)

3 Months Ended

Dec. 31, 2021

Fair Value Disclosures [Abstract]

Summary of Financial Instruments Measured at Fair Value on Recurring Basis

The carrying amounts and estimated fair values of financial instruments not measured at fair value on a recurring basis are shown in the following tables, classified according to the fair value hierarchy. There were no such instruments classified as Level 3 (significant unobservable inputs) as of December 31, 2021, September 30, 2021, and December 31, 2020.

					Classification of Estimated Fair Value
	Carrying Amount		Fair Value		Quoted Prices in Active Markets (Level 1)		Significant Observable Inputs (Level 2)
Spire
As of December 31, 2021
Cash and cash equivalents	$	8.2	$	8.2	$	8.2	$	—
Notes payable		846.0		846.0		—		846.0
Long-term debt, including current portion		3,238.0		3,594.4		—		3,594.4
As of September 30, 2021
Cash and cash equivalents	$	4.3	$	4.3	$	4.3	$	—
Notes payable		672.0		672.0		—		672.0
Long-term debt, including current portion		2,994.9		3,375.9		—		3,375.9
As of December 31, 2020
Cash and cash equivalents	$	3.5	$	3.5	$	3.5	$	—
Notes payable		696.1		696.1		—		696.1
Long-term debt, including current portion		2,628.4		3,119.5		—		3,119.5
Spire Missouri
As of December 31, 2021
Notes payable	$	250.0	$	250.0	$	—	$	250.0
Notes payable – associated companies		180.4		180.4		—		180.4
Long-term debt		1,637.0		1,830.5		—		1,830.5
As of September 30, 2021
Notes payable	$	250.0	$	250.0	$	—	$	250.0
Notes payable – associated companies		240.9		240.9		—		240.9
Long-term debt		1,338.4		1,540.4		—		1,540.4
As of December 31, 2020
Notes payable – associated companies	$	393.7	$	393.7	$	—	$	393.7
Long-term debt		1,092.2		1,329.0		—		1,329.0
Spire Alabama
As of December 31, 2021
Notes payable – associated companies	$	173.7	$	173.7	$	—	$	173.7
Long-term debt, including current portion		571.3		653.6		—		653.6
As of September 30, 2021
Notes payable – associated companies	$	49.0	$	49.0	$	—	$	49.0
Long-term debt		621.2		707.5		—		707.5
As of December 31, 2020
Notes payable – associated companies	$	27.0	$	27.0	$	—	$	27.0
Long-term debt		621.0		742.9		—		742.9